DOI: 10.1016/j.epsl.2017.10.057
Scopus记录号: 2-s2.0-85034247207
论文题名: Methane clumped isotopes in the Songliao Basin (China): New insights into abiotic vs. biotic hydrocarbon formation
作者: Shuai Y. ; Etiope G. ; Zhang S. ; Douglas P.M.J. ; Huang L. ; Eiler J.M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 482 起始页码: 213
结束页码: 221
语种: 英语
英文关键词: abiotic methane
; clumped isotopologue
; coal
; geochemistry
; natural gas
Scopus关键词: Biogeochemistry
; Biological materials
; Carbon dioxide
; Coal
; Crystalline rocks
; Degradation
; Exploratory geochemistry
; Geochemistry
; Geology
; Helium
; Hydrocarbons
; Isotopes
; Methane
; Natural gas
; Organic compounds
; Paraffins
; Petroleum prospecting
; Rocks
; Geochemical features
; Geological conditions
; Hydrocarbon formation
; Isotopic composition
; Isotopologues
; Microbial activities
; Molecular compositions
; Serpentinized ultramafic rocks
; Gases
; coal
; environmental factor
; geochemistry
; hydrocarbon exploration
; isotopic composition
; methane
; natural gas
; China
; Songliao Basin
英文摘要: Abiotic hydrocarbon gas, typically generated in serpentinized ultramafic rocks and crystalline shields, has important implications for the deep biosphere, petroleum systems, the carbon cycle and astrobiology. Distinguishing abiotic gas (produced by chemical reactions like Sabatier synthesis) from biotic gas (produced from degradation of organic matter or microbial activity) is sometimes challenging because their isotopic and molecular composition may overlap. Abiotic gas has been recognized in numerous locations on the Earth, although there are no confirmed instances where it is the dominant source of commercially valuable quantities in reservoir rocks. The deep hydrocarbon reservoirs of the Xujiaweizi Depression in the Songliao Basin (China) have been considered to host significant amounts of abiotic methane. Here we report methane clumped-isotope values (Δ18) and the isotopic composition of C1–C3 alkanes, CO2 and helium of five gas samples collected from those Xujiaweizi deep reservoirs. Some geochemical features of these samples resemble previously suggested identifiers of abiotic gas (13C-enriched CH4; decrease in 13C/12C ratio with increasing carbon number for the C1–C4 alkanes; abundant, apparently non-biogenic CO2; and mantle-derived helium). However, combining these constraints with new measurements of the clumped-isotope composition of methane and careful consideration of the geological context, suggests that the Xujiaweizi depression gas is dominantly, if not exclusively, thermogenic and derived from over-mature source rocks, i.e., from catagenesis of buried organic matter at high temperatures. Methane formation temperatures suggested by clumped-isotopes (167–213 °C) are lower than magmatic gas generation processes and consistent with the maturity of local source rocks. Also, there are no geological conditions (e.g., serpentinized ultramafic rocks) that may lead to high production of H2 and thus abiotic production of CH4 via CO2 reduction. We propose that the Songliao gas is representative of an atypical type of thermogenic gas that can be mistaken for abiotic gas. Such gases may be encountered more frequently in future exploration of deep or over-mature petroleum systems. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110106
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Key Laboratory of Petroleum Geochemistry, Research Institute of Petroleum Exploration and Development (PetroChina), Beijing, China; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma 2, Roma, Italy; Faculty of Environmental Science and Engineering, Babes-Bolyai University, Cluj-Napoca, Romania; Department of Earth and Planetary Sciences, McGill University, Montreal, QC, Canada
Recommended Citation:
Shuai Y.,Etiope G.,Zhang S.,et al. Methane clumped isotopes in the Songliao Basin (China): New insights into abiotic vs. biotic hydrocarbon formation[J]. Earth and Planetary Science Letters,2018-01-01,482